The general invention relates to spreaders, and more particularly to an improved auger design using a motor and transmission to drive a horizontal auger and a separate motor to drive a spinner. Even more particularly, the present invention is directed to an economical, compact spreader having a horizontal auger that is adapted to be mounted upon the rear of a vehicle, such as for example a pick-up truck and to spread salt, sand and other materials.
Conventional rear mounted spreaders have a material delivery system which uses a vertical auger for directing material through an outlet in a hopper. The outlet is typically a circular opening formed by the converging walls of the hopper. Generally, a tubular opening is defined by the walls adjacent to the circular opening and the auger is received within this tubular opening. The blades of the auger are closely adjacent to the walls of this tubular opening. The hopper receives and stores, for example, sand, salt or other materials to be spread. The vertical auger typically rises from the outlet and into the hopper. In conventional spreaders, a rod extends from the auger and attaches to a motor mounted in the hopper that drives the auger.
This type of vertical auger orientation has presented operating problems. Due to moisture or other environmental factors, the material within the hopper can become compacted, particularly adjacent the tubular opening. While the auger effectively directs material contacting the auger through the outlet, the compacted material can cause a cavity to form above the auger preventing material from reaching the auger. Compaction is particularly problematic with sand and bulk salt, which naturally compacts and cavitates in a spreader. Sand and bulk salt will form a cavity directly above the auger and starve the auger.
The present invention overcomes the above problems found in known spreaders and provides many advantages.
The spreader unit of the present invention includes a hopper for holding material to be spread. The hopper includes an opening for receipt of material and an outlet for discharging material. A spinner is mounted to a vertical drive shaft, which is driven by a motor that is controlled from within the vehicle. The spinner receives material from the outlet and throws the material over a large distribution area. The spinner and spinner motor are mounted outside the hopper for easy maintenance and to protect the motor from the corrosive material inside the hopper.
The spreader unit further includes a horizontal auger along the bottom of the hopper to direct material toward the outlet for facilitating the discharge of material from the hopper through the outlet. Preferably, a right angle drive transmission is connected to a separate drive motor, which is connected to the auger for driving the auger. The motor and right angle drive transmission are mounted outside of the hopper to facilitate maintenance and reduce corrosion. In the preferred embodiment, a separate control controls the motor driving the auger. In this way, the auger speed and the spinner speed can be independently set and controlled.
In a further embodiment of the present invention, the drive mechanism includes a dual speed transmission. In this way, the transmission can be designed to drive the auger at one speed and the spinner at a second speed.
The horizontal auger significantly reduces the potential for a cavity forming around the auger due to the opening above the auger being much larger. Instead of a relatively small tubular opening surrounding the auger, there is a long shallow area containing the auger. With the greater area of the opening above the auger, cavitation is greatly reduced because the bottom of the sand or salt continually falls into the opening. The compacted material loses its own support. With the addition of a vibrator assembly, the problem of cavitation is eliminated.
In this way, bulk salt and sand can be spread from a rear mounted spreader. Prior to the present invention, rear mounted spreaders were limited to spreading bagged salt, which doesn""t have the same compaction problems as bulk salt and sand.